Sensor

ABSTRACT

Sensor(s) may be such that light-projecting component(s) and light-receiving component(s) are arranged therein. Furthermore, such sensor(s) may be provided with optical path varying means varying projected light optical path(s) and/or received light optical path(s) so as to physically vary overlapping zone(s). Such optical path varying means may carry out adjustment of optical sensitivity by increasing extent(s) of overlapping zone(s) when carrying out detection with respect to zone(s) distant from such sensor(s) and/or decreasing extent(s) of overlapping zone(s) when carrying out detection with respect to zone(s) proximate to such sensor(s).

BACKGROUND OF INVENTION

This Nonprovisional application claims priority under 35 U.S.C. § 119(a)on patent Application No. 2002-333704 filed in Japan on Nov. 18, 2002,the entire contents of which are hereby incorporated by reference.

The present invention pertains to a sensor detecting entry of object(s)into overlapping zone(s) at which projected light optical path(s) oflight irradiated from light-projecting component(s) overlap receivedlight optical path(s) of light incident on light-receiving component(s).

Conventional sensors include automatic door sensors having the abilityto vary the protected zone for detection of persons travelingtherethrough, as disclosed for example at Japanese Patent ApplicationPublication Kokai No. H3-55381 (1991).

In this automatic door sensor, a light-projecting component and alight-receiving component are disposed above an automatic door. Atwo-piece rotatable mirror is employed as reflecting mirror to reflectlight irradiated from the light-projecting component, the reflectingmirror splitting the light irradiated from the light-projectingcomponent into two beams which irradiate the floor, forming a first zoneproximate to the door, and a second zone which is removed from thisfirst zone. Furthermore, provided at the light-receiving component onwhich reflected light from this first zone and this second zone isincident there is a two-piece rotatable reflecting mirror, reflectedlight beams from the first zone and the second zone being respectivelyreceived by the light-receiving component.

In this automatic door sensor, because the light-projecting andlight-receiving components respectively employ rotatable reflectingmirrors, it is possible through adjustment of the rotational angles ofthese reflecting mirrors to simultaneously relocate the first zone andthe second zone.

Now, it is generally the case with automatic door sensors that thedensity of the light irradiated from the light-projecting component willbe highest near the automatic door sensor, and will decrease as one goesoutside of that region and approaches regions peripheral thereto.Furthermore, if the distance between the light-projecting component andthe light-receiving component arranged therein is varied, then, holdingthe density of the light irradiated from the light-projecting componentconstant, the density of the light irradiated from the light-projectingcomponent will decrease as the distance between the two is increased.

Using the automatic door sensor disclosed at Japanese Patent ApplicationPublication Kokai No. H3-55381 (1991) as an example to illustrate thisfact, the optical path length of the light beam arriving at thelight-receiving component after reflection from the (peripheral) secondzone will be longer than that of the light beam arriving at thelight-receiving component after reflection from the first zone (near thelight-projecting component). For this reason, while it is possible withthis automatic door sensor to vary protected zones so as to formarbitrary protected zones (first zone(s) and second zone(s)), it is notpossible to carry out detection of objects entering protected zones suchthat equivalent light density, i.e., optical sensitivity, is used fordetection thereof across all protected zones. For this reason, takingdetection in the first zone as reference, it will sometimes be the casethat the low light density and low optical sensitivity in the secondzone will prevent detection thereat. Or taking detection in the secondzone as reference, the high light density and high optical sensitivityin the first zone will sometimes cause faulty operation such thatobjects not intended for detection, e.g., paper lying on the ground orthe like, are detected thereat.

In order to solve one or more of the aforementioned problems, it istherefore an object of the present invention to provide a sensor havingability to vary protected zone(s) at which detection of person(s)traveling therethrough and/or other such object(s) are detected andcarrying out detection of object(s) entering protected zone(s) such thatdetection thereof is carried out with equivalent optical sensitivityacross all protected zones despite any varying of protected zone(s).

SUMMARY OF INVENTION

In order to achieve the foregoing object and/or other objects, a sensorassociated with one or more embodiments of the present inventioncomprises one or more light-projecting components irradiating light fromone or more light-projecting surfaces; and one or more light-receivingcomponents receiving at least a portion of the light irradiated from atleast one of the light-projecting component or components, the receivedlight being incident on one or more light-receiving surfaces afterhaving been reflected; the sensor detecting one or more objects in oneor more overlapping zones at which at least one projected light opticalpath of the light irradiated by at least one of the light-projectingcomponent or components at least partially overlaps at least onereceived light optical path of the light incident on at least one of thelight-receiving component or components; the sensor further comprisingone or more optical path varying means varying at least one of theprojected light optical path or paths and/or at least one of thereceived light optical path or paths so as to physically vary at leastone of the overlapping zone or zones; at least one of the optical pathvarying means carrying out adjustment of optical sensitivity byincreasing at least one extent of at least one of the overlapping zoneor zones when carrying out detection with respect to at least onedistant zone and/or decreasing at least one extent of at least one ofthe overlapping zone or zones when carrying out detection with respectto at least one proximate zone.

In accordance with such embodiment(s) of the present invention, becauseoptical path varying means is/are provided, adjustment of opticalsensitivity may be carried out by increasing extent(s) of overlappingzone(s) when carrying out detection with respect to zone(s) distant fromsuch sensor(s) and/or decreasing extent(s) of overlapping zone(s) whencarrying out detection with respect to zone(s) proximate to suchsensor(s). That is, because light density is high when carrying outdetection with respect to zone(s) proximate to such sensor(s),adjustment of optical sensitivity may be carried out so as to decreaseextent(s) of overlapping zone(s); and because light density is low whencarrying out detection with respect to zone(s) distant from suchsensor(s), adjustment of optical sensitivity may be carried out so as toincrease extent(s) of overlapping zone(s). As a result, it will bepossible to carry out detection of object(s) entering overlappingzone(s) such that detection thereof is carried out with equivalentoptical sensitivity across all overlapping zones despite any varying ofoverlapping zone(s).

Furthermore, because optical path varying means may physically varyoverlapping zone(s), it is possible to reduce manufacturing cost ascompared with the alternative of electrically varying same, as there isno need to develop and provide additional controller(s) for varyingoverlapping zone(s).

More specifically, in the foregoing constitution, at least one of theoptical path varying means may be such that one or more translucentcurved bodies is or are disposed in at least one of the projected and/orreceived light optical path or paths; at least one of the translucentcurved body or bodies comprises one or more flat components and one ormore curved components formed in continuous fashion; at least one of thelight-projecting component or components and at least one of thelight-receiving component or components are arrayed in the same order asat least one of the flat component or components and at least one of thecurved component or components formed in continuous fashion; and whencarrying out detection with respect to at least one distant zone, atleast one of the light-projecting component or components and at leastone of the light-receiving component or components are made to moveand/or rotate from at least one of the flat component or components andtoward at least one of the curved component or components whilemaintaining at least one distance between at least a portion of thelight-projecting and light-receiving surfaces of the light-projectingand light-receiving components.

Alternatively or in addition thereto, at least one of the optical pathvarying means may be such that one or more prismatic bodies is or aredisposed in at least one of the projected and/or received light opticalpath or paths; at least one of the prismatic body or bodies presentinggradually increasing angle or angles as one goes from at least one sidethereof to at least one other side thereof; at least one of thelight-projecting component or components and at least one of thelight-receiving component or components are arrayed in the same order asthe at least one side thereof and the at least one other side thereof;and when carrying out detection with respect to at least one distantzone, at least one of the light-projecting component or components andat least one of the light-receiving component or components are made tomove and/or rotate from the at least one side thereof and toward the atleast one other side thereof while maintaining at least one distancebetween at least a portion of the light-projecting and light-receivingsurfaces of the light-projecting and light-receiving components.

Alternatively or in addition thereto, at least one of the optical pathvarying means may be such that one or more mirror bodies is or aredisposed in at least one of the projected and/or received light opticalpath or paths; at least one of the mirror body or bodies comprises oneor more flat components and one or more curved components formed incontinuous fashion; at least one of the light-projecting component orcomponents and at least one of the light-receiving component orcomponents are arrayed in the same order as at least one of the flatcomponent or components and at least one of the curved component orcomponents formed in continuous fashion; and when carrying out detectionwith respect to at least one distant zone, at least one of thelight-projecting component or components and at least one of thelight-receiving component or components are made to move and/or rotatefrom at least one of the flat component or components and toward atleast one of the curved component or components while maintaining atleast one distance between at least a portion of the light-projectingand light-receiving surfaces of the light-projecting and light-receivingcomponents.

Alternatively or in addition thereto, at least one of the optical pathvarying means may be such that one or more rotatable shafts for rotatingat least one of the light-projecting component or components and atleast one of the light-receiving component or components is or aredisposed between at least one of the light-projecting component orcomponents and at least one of the light-receiving component orcomponents; and when carrying out detection with respect to at least onedistant zone, at least one of the light-projecting component orcomponents and/or at least one of the light-receiving component orcomponents is or are rotated in at least one direction such as wouldtend to increase the degree to which at least one of thelight-projecting surface or surfaces faces at least one of thelight-receiving surface or surfaces.

Adoption of the foregoing specific optical path varying meansconstitution(s) makes it possible to eliminate the need to provideadditional member(s) that might be arranged therein only withdifficulty. As a result, it is possible to reduce sensor parts countand/or simplify sensor structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(a) is a schematic diagram of the principal parts of a sensorassociated with a first embodiment, shown at a time when detection isbeing carried out with respect to a proximate zone. FIG. 1(b) is aschematic diagram of the principal parts of the sensor, shown at a timewhen detection is being carried out with respect to a distant zone.

FIG. 2(a) is a schematic diagram of the principal parts of a sensorassociated with a second embodiment, shown at a time when detection isbeing carried out with respect to a proximate zone. FIG. 2(b) is aschematic diagram of the principal parts of the sensor, shown at a timewhen detection is being carried out with respect to a distant zone.

FIG. 3(a) is a schematic diagram of the principal parts of a sensorassociated with a third embodiment, shown at a time when detection isbeing carried out with respect to a proximate zone. FIG. 3(b) is aschematic diagram of the principal parts of the sensor, shown at a timewhen detection is being carried out with respect to a distant zone.

FIG. 4(a) is a schematic diagram of the principal parts of a sensorassociated with a fourth embodiment, shown at a time when detection isbeing carried out with respect to a proximate zone. FIG. 4(b) is aschematic diagram of the principal parts of the sensor, shown at a timewhen detection is being carried out with respect to a distant zone.

DESCRIPTION OF PREFERRED EMBODIMENTS

Below, embodiments of the present invention are described with referenceto the drawings. Note that while the following embodiments apply thepresent invention to an automatic door sensor, this being one type ofsensor, the present invention is not limited thereto, it being possibleto apply the present invention to sensors used in other fields, e.g.,security sensors and the like.

First Embodiment

As shown in FIG. 1, automatic door sensor 1 is such thatlight-projecting component(s) 11, irradiating light fromlight-projecting surface(s) 111; and light-receiving component(s) 12,receiving light irradiated from such light-projecting component(s) 11,the received light being incident on light-receiving surface(s) 121after having been reflected, are arrayed vertically at the time thatthis automatic door sensor 1 is installed. Furthermore, at thisautomatic door sensor 1, cover(s) is/are employed at housing surface(s)facing light-projecting and light-receiving surfaces 111, 121 forallowing light to be irradiated from light-projecting component 11 andincident on light-receiving component 12. Note also that detectionconditions are such that constant density is maintained in the lightirradiated from light-projecting surface 111 of light-projectingcomponent 11.

In accordance with such constitution, this automatic door sensor 1 issuch that object(s) is/are detected at overlapping zone(s) 16 at whichprojected light optical path(s) 14 of light irradiated fromlight-projecting component(s) 11 and transmitted through cover(s)overlaps received light optical path(s) 15 of light transmitted throughcover(s) and incident on light-receiving component(s) 12.

Furthermore, such automatic door sensor 1 may be provided with opticalpath varying means varying projected light optical path(s) 14 and/orreceived light optical path(s) 15 so as to physically vary overlappingzone(s) 16. Such optical path varying means may carry out adjustment ofoptical sensitivity by increasing extent(s) of overlapping zone(s) 16(see FIG. 1 (b)) when carrying out detection with respect to zone(s)distant from the automatic door sensor 1 and/or decreasing extent(s) ofoverlapping zone(s) (see FIG. 1(a)) when carrying out detection withrespect to zone(s) proximate to the automatic door sensor 1.

As shown in FIG. 1, the present optical path varying means is such thattranslucent curved body 13 is disposed in projected and received lightoptical paths 14, 15, the translucent curved body 13 comprising flatcomponent 131 and curved component 132 formed in continuous fashion.Furthermore, light-projecting component 11 and light-receiving component12 are arrayed such that light-projecting component 11 is on the sameside as flat component 131 of translucent curved body 13, andlight-receiving component 12 is on the same side as curved component 132thereof. Moreover, when carrying out detection with respect to zone(s)distant from this automatic door sensor 1, light-projecting andlight-receiving surfaces 111, 121 of light-projecting andlight-receiving components 11, 12 are rotated from flat component 131 oftranslucent curved body 13 toward curved component 132 thereof whilemaintaining the distance between light-projecting and light-receivingsurfaces 111, 121 of light-projecting and light-receiving components 11,12. Note that this translucent curved body 13 may also be employed asthe translucent cover which is the housing of this automatic door sensor1.

Next, referring to FIG. 1, operation of automatic door sensor 1 whencarrying out detection with respect to a zone which is proximate to thisautomatic door sensor 1 and operation thereof when carrying outdetection with respect to a zone which is distant from this automaticdoor sensor 1 will be described.

First, when carrying out detection with respect to a zone which isproximate to this automatic door sensor 1, light-projecting andlight-receiving components 11, 12 are both disposed so as to causelight-projecting and light-receiving surfaces 111, 121 to be directedtoward flat component 131 of translucent curved body 13.

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is transmittedthrough flat component 131. Of this irradiated light, only that portionirradiated along received light optical path 15, i.e., only that portionwhich irradiates overlapping zone 16—at which projected light opticalpath 14 overlaps received light optical path 15—is reflected. Thisreflected light is transmitted through translucent curved body 13 and isincident on light-receiving surface 121, being received bylight-receiving component 12. As shown at FIG. 1(a), the extent ofoverlapping zone 16 at this time is small.

Next, when carrying out detection with respect to a zone which isdistant from this automatic door sensor 1, light-projecting andlight-receiving components 11, 12 are both rotated from flat component131 of translucent curved body 13 toward curved component 132 thereof.At such time, light-receiving surface 121 of light-receiving component12 is disposed so as to be directed at curved component 132, andlight-projecting surface 111 of light-projecting component 11 isdisposed so as to be directed at flat component 131.

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is transmittedthrough flat component 131. Of this irradiated light, only that portionirradiated along received light optical path 15, i.e., only that portionwhich irradiates overlapping zone 16—at which projected light opticalpath 14 overlaps received light optical path 15—is reflected. Thisreflected light is transmitted through translucent curved body 13 and isincident on light-receiving surface 121, being received bylight-receiving component 12. At such time, the light incident thereatbeing refracted by curved component 132, the received light optical path15 undergoes refraction as indicated at FIG. 1(b). Furthermore, as shownat FIG. 1(b), the extent of overlapping zone 16 at this time is large.

As described above, in accordance with the present automatic door sensor1, because translucent curved body 13 is provided, adjustment of opticalsensitivity may be carried out by increasing extent(s) of overlappingzone(s) 16 when carrying out detection with respect to zone(s) distantfrom this automatic door sensor 1 and/or decreasing extent(s) ofoverlapping zone(s) 16 when carrying out detection with respect tozone(s) proximate to this automatic door sensor 1. That is, becauselight density is high when carrying out detection with respect tozone(s) proximate to this automatic door sensor 1, adjustment of opticalsensitivity may be carried out so as to decrease extent(s) ofoverlapping zone(s) 16; and because light density is low when carryingout detection with respect to zone(s) distant from this automatic doorsensor 1, adjustment of optical sensitivity may be carried out so as toincrease extent(s) of overlapping zone(s) 16. As a result, it will bepossible to carry out detection of object(s) entering overlappingzone(s) 16 such that detection thereof is carried out with equivalentoptical sensitivity across all overlapping zones 16 despite any varyingof overlapping zone(s) 16.

Furthermore, because translucent curved body 13 physically variesoverlapping zone(s) 16, it is possible to reduce manufacturing cost ascompared with the alternative of electrically varying same, as there isno need to develop and provide additional controller(s) for varyingoverlapping zone(s) 16.

Furthermore, because translucent curved body 13 is provided therein,this automatic door sensor 1 makes it possible to eliminate the need toprovide additional member(s) that might be arranged therein only withdifficulty. As a result, it is possible to reduce the parts count ofautomatic door sensor 1 and/or simplify the structure of automatic doorsensor 1.

Note also that whereas in the present first embodiment translucentcurved body 13 is employed as the cover which is the housing ofautomatic door sensor 1, the present invention is not limited thereto;it being possible, for example, to separately provide same at theinterior of the housing, provided only that same be disposed inprojected and/or received light optical paths 14, 15.

Furthermore, whereas translucent curved body 13 was disposed inprojected and received light optical paths 14, 15, the present inventionis not limited thereto; it being possible, for example, to disposetranslucent curved body 13 only in projected light optical path 14,varying extent(s) of overlapping zone(s) 16 by refracting only projectedlight optical path 14.

Furthermore, whereas light-projecting component 11 and light-receivingcomponent 12 were arrayed such that light-projecting component 11 was onthe same side as flat component 131 of translucent curved body 13, andlight-receiving component 12 was on the same side as curved component132 thereof, the present invention is not limited thereto; it beingpossible, for example, for light-projecting component 11 andlight-receiving component 12 to be arrayed such that light-receivingcomponent 12 is on the same side as flat component 131 of translucentcurved body 13, and light-projecting component 11 is on the same side ascurved component 132 thereof.

Furthermore, whereas light-projecting component 11 and light-receivingcomponent 12 were arrayed vertically at the time that automatic doorsensor 1 was installed, the present invention is not limited thereto; itbeing possible, for example, to array same horizontally, provided onlythat light-projecting component 11 and light-receiving component 12 arerotated from flat component 131 of translucent curved body 13 towardcurved component 132 thereof while maintaining the distance betweenlight-projecting and light-receiving surfaces 111, 121 oflight-projecting and light-receiving components 11, 12.

Furthermore, whereas light-projecting component 11 and light-receivingcomponent 12 were rotated from flat component 131 of translucent curvedbody 13 toward curved component 132 thereof, the present invention isnot limited thereto; it being possible for light-projecting component 11and light-receiving component 12 to be moved from flat component 131 oftranslucent curved body 13 toward curved component 132.

Next, automatic door sensors associated with other embodiments havingoperation and effect similar to automatic door sensor 1 associated withthe present first embodiment will be described.

Second Embodiment

The automatic door sensor of the second embodiment differs from theautomatic door sensor of the foregoing first embodiment only withrespect to the optical path varying means, the constitutions thereofbeing identical in other respects. Description of the present secondembodiment will therefore be confined to the optical path varying meanswith respect to which it differs from the automatic door sensor of thefirst embodiment, and like constituents will be assigned like referencenumerals and description thereof will be omitted.

As shown in FIG. 2, arranged at automatic door sensor 1 there arelight-projecting component 11 and light-receiving component 12, cover(s)being employed at housing surface(s) facing light-projecting andlight-receiving surfaces 111, 121 of these light-projecting andlight-receiving components 11, 12. Note also that detection conditionsare such that constant density is maintained in the light irradiatedfrom light-projecting surface 111 of light-projecting component 11.

Furthermore, such automatic door sensor 1 may be provided with opticalpath varying means varying projected light optical path(s) 14 and/orreceived light optical path(s) 15 so as to physically vary overlappingzone(s) 16.

As shown in FIG. 2, the present optical path varying means is such thatprismatic body 23 is disposed in projected and received light opticalpaths 14, 15, the prismatic body 23 presenting gradually increasingangles as one goes from one side 231 thereof to the other side 232thereof. Furthermore, light-projecting component 11 and light-receivingcomponent 12 are arrayed in the order “light-projecting component 11 tolight-receiving component 12” as one goes from the one side 231 thereofto the other side 232 thereof. Moreover, when carrying out detectionwith respect to zone(s) distant from this automatic door sensor 1,light-projecting and light-receiving surfaces 111, 121 oflight-projecting and light-receiving components 11, 12 are rotated fromthe one side 231 of prismatic body 23 to the other side 232 thereofwhile maintaining the distance between light-projecting andlight-receiving surfaces 111, 121 of light-projecting andlight-receiving components 11, 12. Note that this prismatic body 23 mayalso be employed as the translucent cover which is the housing of thisautomatic door sensor 1.

Next, referring to FIG. 2, operation of automatic door sensor 1 whencarrying out detection with respect to a zone which is proximate to thisautomatic door sensor 1 and operation thereof when carrying outdetection with respect to a zone which is distant from this automaticdoor sensor 1 will be described.

First, when carrying out detection with respect to a zone which isproximate to this automatic door sensor 1, light-projecting component 11and light-receiving component 12 are disposed so as to causelight-projecting and light-receiving surfaces 111, 121 to be directedtoward prismatic body 23 in the order “light-projecting component 11 tolight-receiving component 12” as one goes from the one side 231 ofprismatic body 23 to the other side 232 thereof.

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is transmittedthrough prismatic body 23. Of this irradiated light, only that portionirradiated along received light optical path 15, i.e., only that portionwhich irradiates overlapping zone 16—at which projected light opticalpath 14 overlaps received light optical path 15—is reflected. Thisreflected light is transmitted through prismatic body 23 and is incidenton light-receiving surface 121, being received by light-receivingcomponent 12 (see FIG. 2(a)).

Next, when carrying out detection with respect to a zone which isdistant from this automatic door sensor 1, light-projecting andlight-receiving components 11, 12 are both rotated from the one side 231of prismatic body 23 to the other side 232 thereof. At such time,light-receiving surface 121 of light-receiving component 12 is disposedso as to be directed at certain angular part(s) 23 a of prismatic body23, and light-projecting surface 111 of light-projecting component 11 isdisposed so as to be directed at certain nonangular part(s) 23 b ofprismatic body 23 (see FIG. 2(b)).

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is transmittedthrough prismatic body 23. Of this irradiated light, only that portionirradiated along received light optical path 15, i.e., only that portionwhich irradiates overlapping zone 16—at which projected light opticalpath 14 overlaps received light optical path 15—is reflected. Thisreflected light is transmitted through prismatic body 23 and is incidenton light-receiving surface 121, being received by light-receivingcomponent 12. At such time, the light incident thereat being refractedby prismatic body 23, the received light optical path 15 undergoesrefraction as indicated at FIG. 2(b).

Third Embodiment

The automatic door sensor of the third embodiment differs from theautomatic door sensor of the foregoing first embodiment only withrespect to the optical path varying means, the constitutions thereofbeing identical in other respects. Description of the present thirdembodiment will therefore be confined to the optical path varying meanswith respect to which it differs from the automatic door sensor of thefirst embodiment, and like constituents will be assigned like referencenumerals and description thereof will be omitted.

As shown in FIG. 3, arranged at automatic door sensor 1 there arelight-projecting component 11 and light-receiving component 12. Notealso that detection conditions are such that constant density ismaintained in the light irradiated from light-projecting surface 111 oflight-projecting component 11.

Furthermore, such automatic door sensor 1 may be provided with opticalpath varying means varying projected light optical path(s) 14 and/orreceived light optical path(s) 15 so as to physically vary overlappingzone(s) 16.

As shown in FIG. 3, the present optical path varying means is such thatmirror 33 is disposed in projected and received light optical paths 14,15, the mirror 33 comprising flat component 331 and curved component 332formed in continuous fashion. Furthermore, light-projecting component 11and light-receiving component 12 are arrayed such that light-projectingcomponent 11 is on the same side as flat component 331 of mirror 33, andlight-receiving component 12 is on the same side as curved component 332thereof. Moreover, when carrying out detection with respect to zone(s)distant from this automatic door sensor 1, light-projecting andlight-receiving surfaces 111, 121 of light-projecting andlight-receiving components 11, 12 are rotated from flat component 331 ofmirror 33 toward curved component 332 thereof while maintaining thedistance between light-projecting and light-receiving surfaces 111, 121of light-projecting and light-receiving components 11, 12.

Next, referring to FIG. 3, operation of automatic door sensor 1 whencarrying out detection with respect to a zone which is proximate to thisautomatic door sensor 1 and operation thereof when carrying outdetection with respect to a zone which is distant from this automaticdoor sensor 1 will be described.

First, when carrying out detection with respect to a zone which isproximate to this automatic door sensor 1, light-projecting component 11and light-receiving component 12 are disposed so as to causelight-projecting and light-receiving surfaces 111, 121 to be directedtoward mirror 33 in the order “light-projecting component 11 tolight-receiving component 12” as one goes from the flat component 331side of mirror 33 to the curved component 332 side thereof.

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is reflected bymirror 33. Of this irradiated light, only that portion irradiated alongreceived light optical path 15, i.e., only that portion which irradiatesoverlapping zone 16—at which projected light optical path 14 overlapsreceived light optical path 15—is reflected. This reflected light isreflected by mirror 33 and is incident on light-receiving surface 121,being received by light-receiving component 12 (see FIG. 3 (a)).

Next, when carrying out detection with respect to a zone which isdistant from this automatic door sensor 1, light-projecting andlight-receiving components 11, 12 are both rotated from flat component331 of mirror 33 toward curved component 332 thereof. At such time,light-receiving surface 121 of light-receiving component 12 is disposedso as to be directed at the curved component 332 side of mirror 33, andlight-projecting surface 111 of light-projecting component 11 isdisposed so as to be directed at the flat component 331 side of mirror33 (see FIG. 3(b)).

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14 and is reflected bymirror 33. Of this irradiated light, only that portion irradiated alongreceived light optical path 15, i.e., only that portion which irradiatesoverlapping zone 16—at which projected light optical path 14 overlapsreceived light optical path 15—is reflected. This reflected light isreflected by mirror 33 and is incident on light-receiving surface 121,being received by light-receiving component 12. At such time, the lightincident thereat being altered by mirror 33, the received light opticalpath 15 undergoes alteration as indicated at FIG. 3(b).

Fourth Embodiment

The automatic door sensor of the fourth embodiment differs from theautomatic door sensor of the foregoing first embodiment only withrespect to the optical path varying means, the constitutions thereofbeing identical in other respects. Description of the present fourthembodiment will therefore be confined to the optical path varying meanswith respect to which it differs from the automatic door sensor of thefirst embodiment, and like constituents will be assigned like referencenumerals and description thereof will be omitted.

As shown in FIG. 4, arranged at automatic door sensor 1 there arelight-projecting component 11 and light-receiving component 12. Notealso that detection conditions are such that constant density ismaintained in the light irradiated from light-projecting surface 111 oflight-projecting component 11.

Furthermore, such automatic door sensor 1 may be provided with opticalpath varying means varying projected light optical path(s) 14 and/orreceived light optical path(s) 15 so as to physically vary overlappingzone(s) 16.

As shown in FIG. 4, the present optical path varying means is such thatrotatable shaft 43 for rotating light-projecting component 11 andlight-receiving component 12 is disposed between light-projectingcomponent 11 and light-receiving component 12. Moreover, when carryingout detection with respect to zone(s) distant from this automatic doorsensor 1, light-projecting and light-receiving components 11, 12 arerotated in the same direction (counterclockwise at FIG. 4(a)), withrotatable shaft 43 serving as axis of rotation; and furthermore,light-projecting and light-receiving components 11, 12 are both rotatedin directions such as would tend to increase the degree to whichlight-projecting surface 111 and light-receiving surface 121 face eachother.

Next, referring to FIG. 4, operation of automatic door sensor 1 whencarrying out detection with respect to a zone which is proximate to thisautomatic door sensor 1 and operation thereof when carrying outdetection with respect to a zone which is distant from this automaticdoor sensor 1 will be described.

First, when carrying out detection with respect to a zone which isproximate to this automatic door sensor 1, light-projecting component 11and light-receiving component 12 are disposed so as to causelight-projecting and light-receiving surfaces 111, 121 to face the samedirection.

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14. Of this irradiatedlight, only that portion irradiated along received light optical path15, i.e., only that portion which irradiates overlapping zone 16—atwhich projected light optical path 14 overlaps received light opticalpath 15—is reflected. This reflected light is incident onlight-receiving surface 121, being received by light-receiving component12 (see FIG. 4(a)).

Next, when carrying out detection with respect to a zone which isdistant from this automatic door sensor 1, light-projecting andlight-receiving components 11, 12 are rotated in the same direction,with rotatable shaft 43 serving as axis of rotation (see rotatable shaft43 at FIG. 4(a)); and furthermore, light-projecting and light-receivingcomponents 11, 12 are both rotated in directions such as would tend toincrease the degree to which light-projecting and light-receivingsurfaces 111, 121 face each other (see FIG. 4(b)).

With the sensor in this state, light irradiated from light-projectingcomponent 11 follows projected light optical path 14. As shown at FIG.4(b), the irradiated light at this time is such that projected lightoptical path 14 is formed in a direction such as will bring it towardreceived light optical path 15. Of this irradiated light, only thatportion irradiated along received light optical path 15, i.e., only thatportion which irradiates overlapping zone 16—at which projected lightoptical path 14 overlaps received light optical path 15—is reflected.This reflected light is incident on the light-receiving surface, beingreceived by light-receiving component 12 (see FIG. 4(b)).

Note also that whereas in the present fourth embodiment when carryingout detection with respect to zone(s) distant from this automatic doorsensor 1, light-projecting and light-receiving components 11, 12 are bymeans of rotatable shaft 43 both rotated in directions such as wouldtend to increase the degree to which light-projecting surface 111 andlight-receiving surface 121 face each other, the present invention isnot limited thereto; it being possible to rotate only eitherlight-projecting component 11 or light-receiving component 12.

As described above with reference to the foregoing first through fourthembodiments, sensors in accordance with embodiment(s) of the presentinvention make it possible to vary protected zone(s) at which detectionof person(s) traveling therethrough and/or other such object(s) aredetected and make it possible to carry out detection of object(s)entering protected zone(s) such that detection thereof is carried outwith equivalent sensitivity with respect to projected and/or receivedlight across all protected zones despite any varying of protectedzone(s).

That is, with sensors in accordance with embodiment(s) of the presentinvention, because optical path varying means may be provided,adjustment of sensitivity with respect to projected and/or receivedlight may be carried out by increasing extent(s) of overlapping zone(s)when carrying out detection with respect to distant zone(s) and/ordecreasing extent(s) of overlapping zone(s) when carrying out detectionwith respect to proximate zone(s). That is, because light density ishigh when carrying out detection with respect to zone(s) proximate tosuch sensor(s), adjustment of optical sensitivity may be carried out soas to decrease extent(s) of overlapping zone(s); and because lightdensity is low when carrying out detection with respect to zone(s)distant from such sensor(s), adjustment of optical sensitivity may becarried out so as to increase extent(s) of overlapping zone(s). As aresult, it will be possible to carry out detection of object(s) enteringoverlapping zone(s) such that detection thereof is carried out withequivalent sensitivity with respect to projected and/or received lightacross all overlapping zones despite any varying of overlapping zone(s).

Furthermore, because optical path varying means may physically varyoverlapping zone(s), it is possible to reduce manufacturing cost ascompared with the alternative of electrically varying same, as there isno need to develop and provide additional controller(s) for varyingoverlapping zone(s).

Furthermore, it is possible to eliminate the need to provide additionalmember(s) that might be arranged therein only with difficulty. As aresult, it is possible to reduce sensor parts count and/or simplifysensor structure.

1. A sensor comprising: one or more light-projecting componentsirradiating light from one or more light-projecting surfaces; and one ormore light-receiving components receiving at least a portion of thelight irradiated from at least one of the light-projecting component orcomponents, the received light being incident on one or morelight-receiving surfaces after having been reflected; the sensordetecting one or more objects in one or more overlapping zones at whichat least one projected light optical path of the light irradiated by atleast one of the light-projecting component or components at leastpartially overlaps at least one received light optical path of the lightincident on at least one of the light-receiving component or components;the sensor further comprising: one or more optical path varying meansvarying at least one of the projected light optical path or paths and/orat least one of the received light optical path or paths so as tophysically vary at least one of the overlapping zone or zones; at leastone of the optical path varying means carrying out adjustment of opticalsensitivity by increasing at least one extent of at least one of theoverlapping zone or zones when carrying out detection with respect to atleast one distant zone and/or decreasing at least one extent of at leastone of the overlapping zone or zones when carrying out detection withrespect to at least one proximate zone.
 2. A sensor according to claim 1wherein: at least one of the optical path varying means is such that oneor more translucent curved bodies is or are disposed in at least one ofthe projected and/or received light optical path or paths; at least oneof the translucent curved body or bodies comprises one or more flatcomponents and one or more curved components formed in continuousfashion; at least one of the light-projecting component or componentsand at least one of the light-receiving component or components arearrayed in the same order as at least one of the flat component orcomponents and at least one of the curved component or components formedin continuous fashion; and when carrying out detection with respect toat least one distant zone, at least one of the light-projectingcomponent or components and at least one of the light-receivingcomponent or components are made to move and/or rotate from at least oneof the flat component or components and toward at least one of thecurved component or components while maintaining at least one distancebetween at least a portion of the light-projecting and light-receivingsurfaces of the light-projecting and light-receiving components.
 3. Asensor according to claim 1 wherein: at least one of the optical pathvarying means is such that one or more prismatic bodies is or aredisposed in at least one of the projected and/or received light opticalpath or paths; at least one of the prismatic body or bodies presentinggradually increasing angle or angles as one goes from at least one sidethereof to at least one other side thereof; at least one of thelight-projecting component or components and at least one of thelight-receiving component or components are arrayed in the same order asthe at least one side thereof and the at least one other side thereof;and when carrying out detection with respect to at least one distantzone, at least one of the light-projecting component or components andat least one of the light-receiving component or components are made tomove and/or rotate from the at least one side thereof and toward the atleast one other side thereof while maintaining at least one distancebetween at least a portion of the light-projecting and light-receivingsurfaces of the light-projecting and light-receiving components.
 4. Asensor according to claim 1 wherein: at least one of the optical pathvarying means is such that one or more mirror bodies is or are disposedin at least one of the projected and/or received light optical path orpaths; at least one of the mirror body or bodies comprises one or moreflat components and one or more curved components formed in continuousfashion; at least one of the light-projecting component or componentsand at least one of the light-receiving component or components arearrayed in the same order as at least one of the flat component orcomponents and at least one of the curved component or components formedin continuous fashion; and when carrying out detection with respect toat least one distant zone, at least one of the light-projectingcomponent or components and at least one of the light-receivingcomponent or components are made to move and/or rotate from at least oneof the flat component or components and toward at least one of thecurved component or components while maintaining at least one distancebetween at least a portion of the light-projecting and light-receivingsurfaces of the light-projecting and light-receiving components.
 5. Asensor according to claim 1 wherein: at least one of the optical pathvarying means is such that one or more rotatable shafts for rotating atleast one of the light-projecting component or components and at leastone of the light-receiving component or components is or are disposedbetween at least one of the light-projecting component or components andat least one of the light-receiving component or components; and whencarrying out detection with respect to at least one distant zone, atleast one of the light-projecting component or components and/or atleast one of the light-receiving component or components is or arerotated in at least one direction such as would tend to increase thedegree to which at least one of the light-projecting surface or surfacesfaces at least one of the light-receiving surface or surfaces.